Merge from branch

(bzr r11950.1.19)

1 files changed, 27 insertions, 16 deletions

diff --git a/src/display/cairo-utils.cpp b/src/display/cairo-utils.cpp
index 692e31837..8eeee0277 100644
--- a/src/display/cairo-utils.cpp
+++ b/src/display/cairo-utils.cpp
@@ -27,6 +27,17 @@
 #include "style.h"
 #include "helper/geom-curves.h"
 
+namespace {
+
+/**
+ * Key for cairo_surface_t to keep track of current color interpolation value
+ * Only the address of the structure is used, it is never initialized. See:
+ * http://www.cairographics.org/manual/cairo-Types.html#cairo-user-data-key-t
+ */
+cairo_user_data_key_t ci_key;
+
+} // namespace
+
 namespace Inkscape {
 
 CairoGroup::CairoGroup(cairo_t *_ct) : ct(_ct), pushed(false) {}
@@ -586,11 +597,11 @@ void ink_cairo_surface_average_color_premul(cairo_surface_t *surface, double &r,
     a = CLAMP(a, 0.0, 1.0);
 }
 
-void srgb_to_linear( guint32* c, guint32 a ) {
+static guint32 srgb_to_linear( const guint32 c, const guint32 a ) {
 
-    *c = unpremul_alpha( *c, a );
+    const guint32 c1 = unpremul_alpha( c, a );
 
-    double cc = *c/255.0;
+    double cc = c1/255.0;
 
     if( cc < 0.04045 ) {
         cc /= 12.92;
@@ -599,16 +610,16 @@ void srgb_to_linear( guint32* c, guint32 a ) {
     }
     cc *= 255.0;
 
-    *c = (int)cc;
+    const guint32 c2 = (int)cc;
 
-    *c = premul_alpha( *c, a );
+    return premul_alpha( c2, a );
 }
 
-void linear_to_srgb( guint32* c, guint32 a ) {
+static guint32 linear_to_srgb( const guint32 c, const guint32 a ) {
 
-    *c = unpremul_alpha( *c, a );
+    const guint32 c1 = unpremul_alpha( c, a );
 
-    double cc = *c/255.0;
+    double cc = c1/255.0;
 
     if( cc < 0.0031308 ) {
         cc *= 12.92;
@@ -617,9 +628,9 @@ void linear_to_srgb( guint32* c, guint32 a ) {
     }
     cc *= 255.0;
 
-    *c = (int)cc;
+    const guint32 c2 = (int)cc;
 
-    *c = premul_alpha( *c, a );
+    return premul_alpha( c2, a );
 }
 
 int ink_cairo_surface_srgb_to_linear(cairo_surface_t *surface)
@@ -636,9 +647,9 @@ int ink_cairo_surface_srgb_to_linear(cairo_surface_t *surface)
             guint32 px = *reinterpret_cast<guint32*>(data + 4*x);
             EXTRACT_ARGB32(px, a,r,g,b)    ; // Unneeded semi-colon for indenting
             if( a != 0 ) {
-                srgb_to_linear( &r, a );
-                srgb_to_linear( &g, a );
-                srgb_to_linear( &b, a );
+                r = srgb_to_linear( r, a );
+                g = srgb_to_linear( g, a );
+                b = srgb_to_linear( b, a );
             }
             ASSEMBLE_ARGB32(px2, a,r,g,b);
             *reinterpret_cast<guint32*>(data + 4*x) = px2;
@@ -661,9 +672,9 @@ int ink_cairo_surface_linear_to_srgb(cairo_surface_t *surface)
             guint32 px = *reinterpret_cast<guint32*>(data + 4*x);
             EXTRACT_ARGB32(px, a,r,g,b)    ; // Unneeded semi-colon for indenting
             if( a != 0 ) {
-                linear_to_srgb( &r, a );
-                linear_to_srgb( &g, a );
-                linear_to_srgb( &b, a );
+                r = linear_to_srgb( r, a );
+                g = linear_to_srgb( g, a );
+                b = linear_to_srgb( b, a );
             }
             ASSEMBLE_ARGB32(px2, a,r,g,b);
             *reinterpret_cast<guint32*>(data + 4*x) = px2;